This standard is issued under the fixed designation C 737; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (e) indicates an editorial change since the last revision or reapproval. | Designation C 737 97 Standard Specification for Limestone for Dusting of Coal Mines1 This standard is issued under the fixed d ii r atic n c 737 the number immediately following the designation indicates the year of original adoption or in the case of revision the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon e indicates an editorial change since the last revision or reapproval. 1. Scope This specification covers lilm l ti lXl suiiablc for use as dust in coal mines to prevent coal dust explosions. Note 1 In coal nine operations limestone is dusted onto coal exposures in sufficient amount so that not less than 65 of all loose dust shall be limestone. With such a concentration of limestone explosions cannot initiate or be propagated from nearby gas explosions. The limestone must be substantially dry in order to dust satisfactorily. 2. Referenced Documents ASTM Standards C 25 Test Methods for Chemical Analysis of Limestone Quicklime and Hydrated Lime2 C 50 Methods for Sampling Inspection Packing and Marking of Lime and Limestone Products2 C 110 Test Methods for Physical Testing of Quicklime Hydrated Lime and Limestone2 3. Chemical Composition Limestone shall conform to the following as to chemical composition 1 This specification is under the . of ASTM CommitStete C-7 on Lime and is the direct responsibility of Subcommittee on Industrial Uses. Current edition approved June 10 1997. Published June 1998. Originally published as C 737-73. Last previous edition C 131 -91. Annual Book of ASTM Standards Vol . Moisture at point of manufacture max Silica free and combined max 4. Physical Properties Limestone for this application shall have the following fineness Passing a No. 20 850-pm sieve min 100 Passing a No. 200 75-pm sieve min 70 5. Test Methods Chemical Analysis The chemical malbi iti off the iimc-stone shall be made in accordance with Test Methods C 25. .
